scholarly journals Progress in the total synthesis of inthomycins

2021 ◽  
Vol 17 ◽  
pp. 58-82
Author(s):  
Bidyut Kumar Senapati
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Biological Activities ◽  
Structural Motif

The inthomycin family of antibiotics, isolated from Streptomyces strains, are interesting molecules for synthesis due to their characteristic common oxazole polyene chiral allylic β-hydroxycarbonyl fragments and significant biological activities. The full structural motif of the inthomycins is found in several more complex natural products including the oxazolomycins, 16-methyloxazolomycin, curromycins A and B, and KSM-2690. This review summarises the application of various efforts towards the synthesis of inthomycins and their analogues systematically.

Total Synthesis of the Pseudoindoxyl Class of Natural Products

2021 ◽  
Author(s):  
Pawan Surendra Dhote ◽  
Pitambar Patel ◽  
Kumar Vanka ◽  
Chepuri Ramana
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Structural Motif ◽  
Large Set

The pseudoindoxyl sub-structural motif, amongst the large set of the indole class of alkaloids, represents a unique subset of the oxygenated indole class of the alkaloids family. A majority of...

scholarly journals Synthetic Approaches to Tetracyclic Pyrrole Imidazole Marine Alkaloids

2013 ◽  
Vol 8 (7) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Takuya Imaoka ◽  
Makoto Iwata ◽  
Takafumi Akimoto ◽  
Kazuo Nagasawa
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Anticancer Activity ◽  
Biological Activities ◽  
Structural Complexity ◽  
Marine Alkaloids ◽  
Ring Systems ◽  
Agonistic Activity ◽  
Synthetic Approaches

Oroidin derived pyrrole imidazole marine alkaloids (PIAs) are attractive targets for synthetic organic chemists because of their structural complexity and diversity as well as their interesting biological activities. A number of efforts have been carried out to develop strategies for the synthesis of these natural products. Members of PIAs ( eg., 2-7) which contain tetracyclic ring systems possessing characteristic cyclic guanidine or urea moieties show significant biological activities including anticancer activity and agonistic activity against the adrenoceptor. In this review investigations of the total synthesis of the representative tetracyclic PIAs dibromophakellin (2) and dibromophakellstatin (3) are described.

Total synthesis of bryostatin 3

Science ◽  
2020 ◽  
Vol 368 (6494) ◽  
pp. 1007-1011 ◽  
Author(s):  
Barry M. Trost ◽  
Youliang Wang ◽  
Andreas K. Buckl ◽  
Zhongxing Huang ◽  
Minh H. Nguyen ◽  
...  
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Marine Natural Products ◽  
Biological Activities ◽  
Step Count ◽  
Total Syntheses ◽  
Linear Sequence ◽  
Wide Range

Bryostatins are a family of 21 complex marine natural products with a wide range of potent biological activities. Among all the 21 bryostatins, bryostatin 3 is structurally the most complex. Whereas nine total syntheses of bryostatins have been achieved to date, bryostatin 3 has only been targeted once and required the highest number of steps to synthesize (43 steps in the longest linear sequence and 88 total steps). Here, we report a concise total synthesis of bryostatin 3 using 22 steps in the longest linear sequence and 31 total steps through a highly convergent synthetic plan by the use of highly atom-economical and chemoselective transformations in which alkynes played a major role in reducing step count.

scholarly journals A General Approach to 2,2-Disubstituted Indoxyls: Total Synthesis of Brevianamide A and Trigonoliimine C

2021 ◽  
Author(s):  
Fan Xu ◽  
Myles Smith
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Bioactive Compounds ◽  
Structural Motif ◽  
Total Syntheses ◽  
Broad Scope ◽  
Nucleophilic Trapping ◽  
General Method

The indoxyl unit is a common structural motif in alkaloid natural products and bioactive compounds. Here, we report a general method that transforms readily available 2-substituted indoles into 2,2-disubstituted indoxyls via nucleophile coupling with a 2-alkoxyindoxyl intermediate and showcase its utility in short total syntheses of the alkaloids brevianamide A (7 steps) and trigonoliimine C (6 steps). The developed method is operationally simple and demonstrates broad scope in terms of nucleophile identity and indole substitution, tolerating 2-alkyl substituents and free indole N–H groups, elements beyond the scope of most prior approaches. Spirocyclic indoxyl products are also accessible via intramolecular nucleophilic trapping.

scholarly journals Synthesis and Structural Confirmation of the Thiazole Alkaloids Derived from Peganum harmala L.

2021 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Myeonghyeon Sim ◽  
Sujin Lee ◽  
Youngtaek Han
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Spectral Data ◽  
Spectroscopic Analysis ◽  
Biological Activities ◽  
Peganum Harmala

Peganumal A and B are thiazole alkaloids isolated from the seeds of Peganum harmala L. Thiazole moieties are rarely found in natural products, but diverse compounds possessing thiazole moieties have attracted attention owing to their broad range of biological activities. Peganumals are the first natural thiazole compounds isolated from the genus Peganum. It was difficult to define the exact structure of peganumal A via spectroscopic analysis. In this paper, we report the first total synthesis of peganumal A and B. The 5-benzylthiazole skeleton possessing methyl or hydrogen at the 2-position of the peganumals was efficiently constructed via the Hantzsch thiazole synthesis of the α-bromoaldehyde intermediate. Moreover, the spectral data of the synthetic 2H–thiazole compound were identical to those previously reported for peganumal A. The synthesis allowed the confirmation of the structure of peganumal A.

scholarly journals Application of asymmetric Sharpless aminohydroxylation in total synthesis of natural products and some synthetic complex bio-active molecules

RSC Advances ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 6634-6659 ◽  
Author(s):  
Majid M. Heravi ◽  
Tahmineh Baie Lashaki ◽  
Bahareh Fattahi ◽  
Vahideh Zadsirjan
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Biological Activities ◽  
Amino Alcohols ◽  
Complex Molecules

This work shows applications of Asymmetric Sharpless Aminohydroxylation (ASAH) in the stereoselective synthesis of vicinal amino alcohols as important intermediates in the total synthesis of complex molecules and natural products with significant biological activities.

The Art of Total Synthesis of Bioactive Natural Products via Microwaves

2021 ◽  
Vol 25 ◽  
Author(s):  
Sasadhar Majhi
Keyword(s):  
Natural Products ◽  
Microwave Irradiation ◽  
Total Synthesis ◽  
Biological Activities ◽  
Complex Structure ◽  
Reaction Times ◽  
Side Reactions ◽  
Bioactive Natural Products ◽  
Classical Methodology ◽  
Green Technique

: Natural products are the most effective source of potential drug leads. The total synthesis of bioactive natural products plays a crucial role to confirm the hypothetical complex structure of natural products in the laboratory. The total synthesis of rare bioactive natural products is one of the great challenges for the organic synthetic community due to their complex structures, biochemical specificity, and stubborn stereochemistry. Subsequently, the total synthesis is a long process in several cases and it requires a substantial amount of time. Microwave irradiation has emerged as a greener tool in organic methodologies to reduce reaction times from days and hours to minutes and seconds. Moreover, this non-classical methodology increases product yields and purities, improves reproducibility, modifications of selectivity, simplification of work-up methods, and reduces unwanted side reactions. Such beneficial qualities have stimulated this review to cover the application of microwave irradiation in the field of the total synthesis of bioactive natural products for the first time during the last decade. An overview of the use of microwave irradiation, natural sources, structures, and biological activities of secondary metabolites is presented elegantly, focusing on the involvement of at least one or more steps by microwave irradiation as a green technique.

C–O Containing Natural Products

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Biological Activities ◽  
Max Planck ◽  
Penicillium Species ◽  
Antimitotic Agent ◽  
Berkelic Acid ◽  
Metal Catalyzed ◽  
The University

It is thought that the pseudopterane class of diterpenoid natural products, of which 11-gorgiacerol is a member, arises biosynthetically by a photo-ring contraction of the related furanocembranes. Johann Mulzer at the University of Vienna has applied (Org. Lett. 2012, 14, 2834) this logic to realize the total synthesis of 11-gorgiacerol. Ringclosing metathesis of the butenolide 1 using the Grubbs second generation catalyst produced the tricycle 2. When irradiated, 2 undergoes a 1,3-rearrangement to furnish the natural product in good yield. Whether this rearrangement is concerted, or occurs stepwise via a diradical intermediate, is not known. Although ring-closing metathesis has become a reliable method for macrocycle construction, its use here to set what then becomes an extracyclic olefin is notable. Berkelic acid is produced by an extremophile bacterium penicillium species that lives in the toxic waters of an abandoned copper mine, and this natural product has been found to possess some very intriguing biological activities. Not surprisingly, berkelic acid has attracted significant attention from synthetic chemists, including Francisco J. Fañanás of Universidad de Oviedo in Spain, who has developed (Angew. Chem. Int. Ed. 2012, 51, 4930) a scalable, protecting-group free total synthesis. The key step in this route is the remarkable silver(I)-catalyzed coupling of alkyne 3 and aldehyde 4 to produce, after hydrogenation, the structural core 5 of (–)-berkelic acid on a gram scale. Some tools from the field of organocatalysis have been brought to bear (Angew. Chem. Int. Ed. 2012, 51, 5735) on a new total synthesis of the macrolide (+)-dactylolide by Hyoungsu Kim of Ajou University in Korea and Jiyong Hong of Duke University. The bridging tetrahydropyranyl ring is fashioned by way of an intramolecular 1,6-oxa conjugate addition of dienal 6 to produce 8 under catalysis by the secondary amine 7. Following some synthetic manipulations, the macrocyclic ring 12 is subsequently forged by an NHC-catalyzed oxidative macrolactonization using the carbene catalyst 10 and diphenoquinone 11 as the oxidant. A new approach to the nanomolar antimitotic agent spirastrellolide F methyl ester has been reported (Angew. Chem. Int. Ed. 2012, 51, 8739) by Alois Fürstner of the Max-Planck-Institut, Mülheim. Two elegant metal-catalyzed processes form the key basis of this strategy.

Natural Products: Key Prototypes to Drug Discovery Against Neglected Diseases Caused by Trypanosomatids

2020 ◽  
Vol 27 (13) ◽  
pp. 2133-2146 ◽  
Author(s):  
Marina Themoteo Varela ◽  
João Paulo S. Fernandes
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Neglected Tropical Diseases ◽  
Biological Activities ◽  
Neglected Diseases ◽  
Synthetic Compounds ◽  
Structural Variety ◽  
The World ◽  
Leishmania Spp ◽  
Per Se

Background: Neglected tropical diseases are a group of infections caused by microorganisms and viruses that affect mainly poor regions of the world. In addition, most available drugs are associated with long periods of treatment and high toxicity which limits the application and patient compliance. Investment in research and development is not seen as an attractive deal by the pharmaceutical industry since the final product must ideally be cheap, not returning the amount invested. Natural products have always been an important source for bioactive compounds and are advantageous over synthetic compounds when considering the unique structural variety and biological activities. On the other hand, isolation difficulties and low yields, environmental impact and high cost usually limit their application as drug per se. Objective: In this review, the use of natural products as prototypes for the semi-synthesis or total synthesis, as well as natural products as promising hits is covered, specifically regarding compounds with activities against trypanosomatids such as Trypanosoma spp. and Leishmania spp. Methods: Selected reports from literature with this approach were retrieved. Conclusion: As summary, it can be concluded that natural products are an underestimated source for designing novel agents against these parasites.

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